marcheshvan

The gemara (Meg 27b) has a din that one should not use the bathroom right after finishing shmoneh esrei until one has waited the time it takes to walk 4 amos.  The gemara explains:  אמר רב אשי שכל ד"א תפלתו סדורה בפיו ורחושי מרחשן שפוותיה  Tefilah does not end the second you finish the last word -- it takes a moment to "recover" from the experience provided one is locked in and engaged as one should be.  It is like one's lips are still moving even after one has ceased to say the words.

This sevara of מרחשן שפוותיה is almost the exact letters as the name of our month, מרחשׁון (no, I am not going to debate you if you insist the name is חשׁון).  Derech remez, it defines the essence of our month.  Tishrei is the month of tefilah, of teshuvah, of making a kabbalah to achieve more.  It's not all over once Tishrei ends.  רחושי מרחשן שפוותיה - the prayers of the chagim are over, but it's like our lips are still moving.  We have to carry the experience and that high level of engagement into the next month and forward into the rest of the year.